Abstract
CONTEXT: The hemodynamic response associated with laryngoscopy and tracheal intubation is a common concern for the anesthesiologist, especially in high-risk patients. The use of dexmedetomidine has found favor in obtunding this response, in addition to providing better intubating conditions and reducing the dose of other anesthetic drugs. Most of the current literature states a loading dose of 1 μg/kg dexmedetomidine to be superior to lower doses in this regard. However, using a lower dose may be advantageous by reducing incidence of adverse effects such as hypotension and bradycardia which are likelier with the use of higher dose, in addition to being more cost-effective. AIMS: The aim of the study was (1) to evaluate and compare the effect of loading doses of 1 μg/kg and 0.5 μg/kg dexmedetomidine on attenuation of hemodynamic response to laryngoscopy and intubation and (2) to evaluate the efficacy of dexmedetomidine in reducing the induction dose of propofol for achieving better intubating conditions. MATERIALS AND METHODS: A randomized, double-blind, placebo-controlled study was planned on ninety American Society of Anesthesiologists I and II patients scheduled for elective surgery under general anesthesia. Patients were divided into three groups. Two groups received different loading doses of dexmedetomidine infusion before induction and the third group was a control group. The induction dose of propofol required to abolish the verbal response was noted and compared in all the three groups. All patients were assessed for the intubating conditions and hemodynamic response. STATISTICAL ANALYSIS: Nonparametric data were compared using the Chi-square test and parametric data were compared using Student's t-test using SPSS 16.0 software. RESULTS: Both the loading doses of 1 μg/kg and 0.5 μg/kg dexmedetomidine were equally effective in reducing the induction dose of propofol, improving the intubating conditions and blunting the hemodynamic response to laryngoscopy and intubation. The incidence of adverse effects such as hypotension and bradycardia was lesser with the loading dose of 0.5 μg/kg. CONCLUSIONS: Dexmedetomidine when used as infusion in the loading dose of 0.5 μg/kg is therapeutically as effective as when used in the dose of 1.0 μg/kg not only in reducing the induction dose of propofol but also in providing good intubating conditions and blunting the hemodynamic response to intubation. A lower dose is associated with a lesser incidence of adverse effects such as hypotension and bradycardia.